Hypoxia-induced Endothelial Barrier Dysfunction

缺氧引起的内皮屏障功能障碍

• 批准号: 7330337
• 负责人: Usamah S Kayyali
• 金额: $ 30.91万
• 依托单位: TUFTS MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-07 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7330337
• 关键词: Actins; Adherent Culture; Adhesions; Altitude; Biomechanics; Blood Vessels; Cardiac; Cells; Cytoskeleton; Development; Disruption; End Point; Endothelial Cells; Endothelium; Event; Exposure to; Functional disorder; HSPB1 gene; Human; Hypoxia; Knock-out; Lead; Link; Liquid substance; Lung; MAPK14 gene; Mediating; Modeling; Mus; Myosin Light Chains; Pathway interactions; Permeability; Phosphorylation; Phosphotransferases; Physiological; Property; Pulmonary Edema; Pulmonary artery structure; Pulmonology; Rattus; Rho-associated kinase; Signal Pathway; Signal Transduction; human MAPK14 protein; in vivo; inhibitor/antagonist; insight; mitogen-activated protein kinase p38; monolayer; novel therapeutics; programs; research study; response; rho

DESCRIPTION (provided by applicant): Non-cardiac pulmonary edema is a frequent affliction in pulmonary medicine and is caused by endothelial barrier dysfunction. It is now recognized that this dysfunction may be initiated by programmed cell signaling as opposed to non-specific disruption of the vascular barrier. Since the endothelial barrier is known to be altered by exposure to hypoxia leading to pulmonary edema, we have utilized a rat pulmonary artery microvascular endothelial cell (EC) monolayer culture model to study the effects of hypoxia on EC barrier function. Preliminary studies have led to the hypothesis that exposure to hypoxia initiates cell signaling through the p38 MAP kinase pathway involving MK2 and HSP27 activation that leads to actin cytoskeleton and hic-5 redistribution. These signaling events are associated with an alteration in biomechanical "tethering" and "stiffness" and enhanced permeability of the EC monolayer. "Tethering" may be regulated by the p38 MAP kinase pathway while "stiffness" is regulated by Rho/Rho kinase and myosin light chain phosphorylation. We plan in the present proposal to study these responses more thoroughly in the rat pulmonary artery microvascular EC monolayer and to perform confirmatory studies in similar cells from human pulmonary microvasculature. In addition, we will investigate these signaling pathways in mice in vivo using pharmacological inhibitors, as well as mice in which the expression of MK2, a key kinase in the p38 pathway, has been "knocked-out". Specifically, we plan to: Aim 1: Define signaling pathways important for mediating cytoskeletal changes in endothelial cell monolayers exposed to hypoxia; Aim 2: Determine the relevance of the biomechanical endpoints "stiffness" and "tethering", which increase with exposure to hypoxia, to physiological determinants of endothelial barrier function; and Aim 3: Evaluate the signaling events that lead to increased pulmonary endothelial permeability in hypoxia in vivo. The findings of this study are expected to further our understanding of mechanisms involved in the development of endothelial barrier dysfunction, in general, and to suggest targets for treatment of pulmonary edema.

描述（由申请人提供）：非心脏肺水肿是肺部医学中常见的痛苦，是由内皮屏障功能障碍引起的。现在已经认识到，这种功能障碍可能是通过程序性细胞信号传导引发的，而不是血管屏障的非特异性破坏。由于已知内皮屏障会因暴露于缺氧而导致肺水肿的缺氧而改变，因此我们利用了大鼠肺动脉微血管内皮细胞（EC）单层培养模型来研究缺氧对EC屏障功能的影响。初步研究导致了以下假设：暴露于缺氧的情况下，通过涉及MK2和HSP27激活的p38 MAP激酶途径引发细胞信号传导，从而导致肌动蛋白细胞骨骼和HIC-5重新分布。这些信号事件与生物力学“束缚”和“刚度”的改变以及EC单层的渗透性增强有关。 “束缚”可以由p38 MAP激酶途径调节，而“刚度”由Rho/Rho激酶和肌球蛋白轻链磷酸化调节。我们在本提案中计划在大鼠肺动脉微血管EC单层中更彻底地研究这些反应，并在人类肺微血管造成的相似细胞中进行验证性研究。此外，我们将使用药理学抑制剂以及MK2的表达（p38途径中的关键激酶表达）被“敲除”。具体而言，我们计划：AIM 1：定义信号通路对于介导暴露于缺氧的内皮细胞单层的细胞骨架变化很重要；目标2：确定生物力学终点“刚度”和“绑扎”的相关性，随着暴露于缺氧而增加，与内皮屏障功能的生理决定因素相关； AIM 3：评估信号事件，导致体内缺氧的肺内皮渗透性增加。总的来说，这项研究的发现将进一步了解我们对内皮屏障功能障碍发展的机制的理解，并提出了治疗肺水肿的靶标。